I got to thinking about my spare a couple of weeks ago driving through a national forest. Well, I took it down today to have a look. I noticed the wheel was a 15" wheel along with a 31x10.5x15 tire. The wheels on my truck are LT245\75\16. Will this be a problem if I have to use the spare? They looked to be the same size when I placed the spare against the mounted tire.


I also noticed that the space where the spare resides doesn't have a lot of extra room. If I were to buy a 16" wheel and tire to match the rest, would it fit in there?

 

245/75R16 is a 31" tire.

So they are the same diameter, no issue using 31x10.5x15 spare.

And since they are the same size then no problem replacing spare with 245/75R16 tire and wheel

 

Thanks, I wasn't sure.

One more question, what would the metric size be for that tire? I'm just looking for a decent used tire to replace the worn spare. I don't want to buy a wheel too.

Anyhow, it seems to be easier to find using the metric size. I found a calculator online and it said 267/76R15 is the equivalent. Of course 265/75/15 is closest, but it is a little smaller (30.4" vs 31"). Is that going to cause any problems?

 

No, no problems, it is close enough to use long term.

The front axle is OPEN so no problem there
Rear axle could be OPEN or Limited Slip, L/S would just think it is going around a long slight curve all the time with one tire of a different diameter

You shouldn't use TWO smaller or larger tires on the front or rear axles with a 4x4, if you use 4WD, then the issue moves to transfer case it needs to slip because front and rear driveshafts are turning at different speeds.

 

31x10.5-15 is a standard size tire. Trying to find a metric size tire equivalent seems to be more trouble than it is worth. Metric size tires are usually more expensive too.

BTW 31" tires are usually around 30.5" and will vary depending on the manufacturer. Metric tires vary similarly.

 

Yes, usually smaller than advertised, rubber ain't cheap